不同年限设施菜地番茄细胞壁果胶Cd累积的研究

为探讨不同种植年限和设施菜地番茄细胞壁果胶Cd累积的关系,以种植年限为2年和14年设施菜地番茄为研究对象,测定了不同种植年限下番茄茎、叶细胞壁果胶含量,并对细胞壁果胶含量、果胶甲酯酶(PME)活性与种植年限及Cd累积量之间的相关性进行了分析。结果表明,随着种植年限的增加,番茄植株各器官Cd累积量均有所增加;种植14年设施菜地番茄茎中Cd累积量比种植2年的增加了24.55%,叶片中Cd累积量增加了45.96%;种植14年设施菜地番茄茎细胞壁Cd累积量增加了61.86%,叶片细胞壁Cd累积量增加了57.46%;不同种植年限设施菜地番茄茎和叶细胞壁果胶Cd含量也存在极显著差异(P0.05)。另外,随着种植年限的增加,番茄茎、叶细胞壁果胶含量和PME活性随之升高:与种植2年相比,种植14年设施菜地番茄茎中果胶含量提高了104.51%,叶片果胶含量提高了127.45%;种植14年设施菜地番茄茎中PME活性提高了10.56%,叶片PME活性提高了9.39%。果胶含量及PME活性和细胞壁Cd累积量呈正相关。研究发现不同年限设施菜地土壤全Cd和有效Cd含量有所不同,影响着番茄不同器官果胶含量及PME活性,说明细胞壁果胶在缓解番茄Cd毒害中起着一定的作用。

Accumulation of Cd in cell wall pectin of tomato plants grown in greenhouse soil of different planting years

Total and available Cd content in soil is known to increase with increase in the number of planting years; therefore, the pectin content, pectin methyl esterase(PME) activity, and Cd content in pectin from different organs in tomato plants(Lycopersicon esculentum) will also be affected. To investigate the effects of greenhouse soil of different planting years on Cd accumulation in pectin of tomato plants, a field study was performed using tomato plants that were grown in soil aged for 2 and 14 planting years. The pectin contents in stem and leaf cell walls were determined, and the correlations between cell wall pectin content, PME activity, planting years, and Cd content were analyzed. The results showed that Cd accumulation in all organs increased with the increase in planting years. Compared to plants that were grown in greenhouse soil of 2 planting years, Cd accumulation increased by 24.55% in stems and 45.96% in leaves of plants that were grown in soils of 14 planting years. In addition, Cd accumulation increased by 61.86% and 57.46% in stem cell walls and leaf cell walls, respectively. Therefore, Cd accumulation in the pectin of cell walls was significantly different owing to different planting years(P<0.05). In addition, with the increase of planting years, pectin content and PME activity in cell walls also increased. Pectin content increased by 104.51% in stems and 127.45% in leaves, and PME activity increased by 10.56% in stems and 9.39% in leaves. Both pectin content and PME activity were positively correlated with cell wall Cd accumulation. Overall, results from the present study demonstrated that total and available Cd content in soil were influenced by different planting years, which affected pectin content and PME activity in different organs of tomato plants. This indicates that cell wall pectin plays a key role in alleviating Cd toxicity in tomato plants.